Wooden truss-bridge



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www www n www? MFEYES, FHOTO-LITMOGRAPNER, WASHINGTON. D'C.

r UNITED `s MARK sULLrvAN, JAQQFKFSSLFF, AND'V1 IJoslin-r l1 F., Fosrnn, oF DUBUQUF.,

PATENTl ,OFFICE pea 1 .SPECIHGATIQF raming .Qof L applicati@ flied Augsn 13, im.V

To all whom t may concern.-

Be it known that we, MARK SULLIVAN,`

J Aeon4 KEssLFR, and 1 J osIAH. R. Festina, of Dubuque, in the county o f Dubuque and State to the letters of reference marked thereonr The object we have in view is to construct.1 .a truss-bridge so thatv the necessary strength can be obtained with fewerandvlighter timbers, and so that theV chords,iwhen1"madeof wood, will be preserved from decayiaitheir ends. i i y Our invention therein consists in the man ner yof constructin g and arranging theflooringtimbers of the bridge so that they will be partly self-supportin g, and so that the ends of `the straight chords or tie-beams.Willfnot'haveto4 be buried in earth; and, further, in the peculiar construction of the truss, made without piercing or boring any o f the timbers,which y than heretofore to obtain the required strength,

` all as fully hereinafter explained.

In the drawings, Figure 1 isa side elevation of our bridge when made in two sections; Fig. 2, a central longitudinal section of the same; Fig. 3, a similar section through one chord; Fig. 4, a separate view of one of the cap-plates; Fig. 5, a separate view of one of the stirrups; Fig. 6, a side elevation of our bridge when made in three sections; Fig. "7, a sectional view, showing th'e manner of sup# porting the three-section iiooring; Figs. 8 and 9, views, similar to Figs. 6 and?, of a bridge having four sections of ooring.

Like letters denote corresponding parts'.

The bridge having two sections of, flooring is builtin the following manner: Upon the abutments A are laid the raised corner-'stones d, upon which Vstones rest the ends of the chords or tie-beams B, preferably of wood. By means of the corner-stones a thechords are raised at their ends above the abutments, for a purpose to be presently described.

The inclined braces() on each chord, and forming part of each truss, are beveled at their Vlowerends where they rest upon :the chord,

and are thererigidly secured to the chord by U- shaped stirrups 1D, which have screwthreaded ends passing through. plates D and -securedihy nuts b.`-`-The stirrups are inclined inwardly `at right angles to the line of inclination of the braces, fand they rest in grooves c in the underside of the chords, to enable them `to resist thestrain without sliding upon the l chords. i

At their upper ends the braces are beveled and rest against eachother.` -No queen-posts are used; but upon the top angle of each pair of braces is placed a cap piece -or plate, E.

`Thesecap-.platesflilare made of metal, have angular underfaces, d, ywhich fit the angle made by the meeting ends of the braces, strengthening-ribs d 'on theirupper faces, and extend 0n each sidebeyond the braces.

`'Ihrough Aeachcap -plate, 'outside of the braces, are passed four rods, F, secured by nuts,`whichro ds extend directly down, passing twoo'n each side Vof the `chord. or` tiebeam below, and on each side of acentral transverse binding-joist, G, andthrough a plate or crossed straps e, on theunder" side of such joist G; The rods Fare-secured by nuts at one or both ends,'which aretightened to draw and secure the parts of each truss firmly and rigidly together.l u The central binding-joist, G, (which is 'the only'one used in the two-section bridge,) extends transversely beneath both chords and the cap-plates E; 'but'these braces may be dispensed with. A

lt will be seen that by using the stirrups to bind the ends of the braces, and by using the peculiar cap-plates and outside rods, none of the timbers are pierced by bolts,which.weaken the parts very materially, and therefore much lighter timbers can be used to gain the necessary strength; and, also, it will be observed that with our construction no queen-posts are required, which is a saving in timber and makes the bridge lighter. Y The longitudinalsills H, to which the iiooring of the bridge is secured, are laid upon the IOO ]'oist G with abutting ends, and incline or curve downwardly from such joist to their outer ends, which rest against the abutments and the lling between the corner-stones a.

The tops of the sills H are made, preferably, curved, so that there will be a gent-1e rise from the ends to the center ot' the bridge.

It will be seen that by this manner ot' constructing the iooring ot' a bridge the sills will brace each other, and the abutments will take the thrust independent of the truss, making the flooring partly selfsnpporting, so that the truss will be greatly relieved from the weight Iof travel.A This double inclination of the door of the bridge also serves to carry off the water and keep the timbers dry. By this arrangement of the sills the flooring I at the center of the bridge is nearly or quite' on a level with the top ot the chords, while at its outer ends it is about on a level with the under faces of such chords or the tops of the corner-stones. The approaches to the bridge are built or graded up to the ends of the ooring, but the ends of the chords are not covered at all with earth.

Heretofore in this style of bridge it has been necessary to cover the ends of the wooden chords with earth in grading the approaches to the bridge, which has caused such chords soon to decay, while the other parts of the bridge were in sound condition. With our construction, however, this objection is avoided.

When the width ot' the stream requires a longer bridge, our bridge can be madein three, fonr,or1nore sections. When made in three sections, Figs. 6 and 7, there is placed between the inclined truss-braces C, on each side, a horizontal lengthening truss-beam, K, beveled at its ends, as shown. At the ends of the truss-beam, over the joints with the braces, are placed half cap-plates L, having horizontal and inclined under faces, ll. These cap-plates extend beyond the sides of the truss braces and beams, and have long rods F extending down to plates or straps e on the under side of two joists, Gr. The flooring-sills H', extending between the two joists Gr, are crowned or curved on their upper sides to preserve the curve of the ooring. No queen-posts are' used, and outside braces, G', Fig. l, may be employed.

For bridges of four or more sections, Figs. 8 and 9, the chords and truss-beams are made proportionately longer, and at one or more points intermediate between the joints at the ends of the truss-beam are placed dat capplates m, extending beyond the sides of the truss-beam and secured to rods F, supporting binding-joists below. The oor-sills are curved to give the crown to the oorin g of the bridge.

What we claim as our invention is l. In a wooden truss-bridge, the combination of the truss-frames having straight Wooden chords B, resting upon the abutments above the road-filling, one or more transverse binding-joists G, supported below the cords by rods from the braces G of the truss-frames, and the flooring-timbers H,inclined or curved upwardly from the abutments between and below the ends of the chords to such binding joist or `joists, whereby the cords are preserved from decay and the ilooring-timbers are made partially selfsnstainin g, substantially as described and shown.

2. In combination, the straight wooden chords, inclined braces secured to thechords by stirrups, angular cap-plates, one or more transverse binding-joists hung from the cap-plates by rods passing down oh the outside of the truss-timbers, and the floorin g-timbers inclined or curved upwardly from the abutlnents to the centeroi' the bridge, substantially as described and shown.

This specification signed and witnessed this 23d day of June, 1879.

MARK SULLIVAN. J AGOB KESSLER. JOSIAH R. FOSTER, Witnesses:

GEO. K. THOMPSON, MONROE M. GABY. 

